This invention relates to the field of air deployable decoy devices and especially to the class of decoy devices usable against infrared responsive night vision equipment.
Military forces operating in a nighttime environment can emit infrared signatures that are detectable by enemy forces using night vision devices. These infrared signatures may originate in such apparatus as the flame from burning materials, even cigarette lighters, from flashlights, and of course from hot equipment such as vehicle engines and exhaust systems. A typical example of such emissions was illustrated in the recent desert storm military campaign wherein the United Nations forces were able to detect the sun heated barrels of enemy tank guns contrasted against the cooler nighttime desert sand with the use of infrared detection equipment.
With careful consideration such infrared signature emissions can be greatly decreased and even largely eliminated. Such reductions can be made even more effective with the use of stronger decoy signals originating in a close-by but unoccupied area where the receipt of enemy air action or artillery rounds is of little consequence and perhaps even helpful in enabling an understanding of enemy intentions and capabilities. The careful placement of a plurality of such infrared signal emitting decoy devices may be accomplished by both ground based and airborne dispersal techniques, e.g. a dispersal as simple as tossing such devices out of an open helicopter door. Such devices may be prearranged to emit a variety of infrared energy flash signals and also to have a variety of flash duration and inter-flash delay intervals so that the viewing of a group of these decoy devices from a distant ground or airborne perspective suggest the random activity of group of personnel.
Infrared signal emitting devices of this type may also be useful to provide terrain marking for such purposes as the interjection or extraction of military forces, and for target marking, especially with the use of smart monitors or heat seeking explosive devices. Although devices of this nature may be made responsive to any portion of the electromagnetic energy spectrum, including the radio frequency and visible light portions of the spectrum, practical considerations and the present day high development state of infrared equipment suggest that the infrared spectral region between 400 and 1100 nanometers of wavelength is of most interest for operating such decoy devices.
The patent art indicates the presence of inventive interest in the field of decoy devices and other apparatus relating as general background to the present invention. Several patents of this general background interest with respect to the present invention include U.S. Pat. No. 3,902,172 of Albert Weiss et al which is concerned with an infrared gated radio fuseing system wherein the detonation of amunitions device is accomplished through the use of both an infrared and a radio frequency signal. In the Weiss et al apparatus, the infrared signal is used to enable the radio frequency signal channel so that both proximity to the intended infrared energy emitting target and receipt of a radio frequency signal are required to accomplish the detonating event. Since the Weiss et al apparatus is concerned with munitions detonation, the present invention decoy apparatus is readily distinguished.
The patents of general background interest with respect to the present invention also include U.S. Pat. No. 4,705,477 which is issued to R. B. Komorowski et al and is concerned with a simulation of aerial decoy arrangements. In the Komorowski patent there is provided an apparatus for simulating a plurality of launcher barrels and the associated isolator module of an aerial infrared or chaff decoy arrangement. Since the Komorowski et al invention is concerned with decoy-rocket launching apparatus and its simulation, a ready distinction between the present invention and the Komorowski et al disclosure is apparent.
These patents of interest also include U.S. Pat. No. 4,478,581 issued to W. Goda et al and concerned with a score keeping and accuracy determining arrangement for gunnery practice. The Goda et al invention involves ballistic ammunition as opposed to remotely controlled ammunition. The Goda et al patent is also concerned with a moving target and with laser accomplished measurements relating to this target as a part of accuracy and score keeping operations. Since the Goda et al apparatus is concerned with gunnery practice and its scoring and not with the provision of decoy apparatus for misinforming an adversary, the present invention is readily distinguished.
These patents of general interest are also inclusive of the U.S. Pat. No. 3,320,420 issued to M. R. Paglee et al which is concerned with an infrared detection system for use in the early stages of a missile launch event. In these early stages, there are rapid angular position changes which, together with ground clutter, complicate the task of tracking the missile with radar. According to the Paglee et al apparatus a supplementary infrared detector is disengaged after some point in the missile's flight and reliance on the normal radar signal ensues. Since the Paglee et al apparatus is concerned with the tracking of an infrared emission source rather than the supplying of deceptive infrared signals, a ready distinction between the present invention and the Paglee et al apparatus is apparent.
The patent art of general interest with respect to the present invention also includes U.S. Pat. No. 4,700,190 issued to J. J. Harrington and concerned with a decoy device in the form of a missile. The Harrington patent is also concerned with enhancing the radar signal or radar cross-section of this decoy missile. This may be used in a multiple reentry vehicle missile system in order to deceive defending radar systems into a belief that each of the multiple reentry warheads is in fact a destructive vehicle rather than a decoy vehicle. Although the Harrington apparatus is concerned with decoy devices a distinction between the present invention night vision and ground deployed decoy devices and the missile decoy of the Harrington invention is readily discerned.